Sensitive Electrochemical Sensor for Determination of Methyldopa Based on Polypyrrole/Carbon Nanoparticle Composite Thin Film Made by In Situ Electropolymerization

Abstract

A composite surface coating is prepared by electropolymerization of a mixture of pyrrole and carbon nanoparticles onto a glassy carbon electrode (GCE). The microscopic structure and morphology of the composite film is characterized by scanning electron microscopy. The modified electrode offers a considerable improvement in voltammetric sensitivity toward methyldopa (m-dopa), compared to the bare and polypyrrole-coated GCEs. A significantly enhanced anodic peak current together with a remarkable increase in sharpness of the cyclic voltammetric (CV) signals are observed for the detection of m-dopa. The effect of experimental parameters, such as scan rate and pH, are investigated by monitoring CV responses toward m-dopa. It is found that a maximum current response can be obtained at pH 3.0 under a diffusion controlled process. A wide linear dynamic range (0.2-50 mM) with a detection limit of 60 nM is achieved for m-dopa. The excellent response characteristics, e.g., high sensitivity, very good repeatability and reproducibility, and low detection limit, have made the prepared sensor suitable for the analysis of mdopa in pharmaceutical and clinical preparations.

Application of multivariate optimization to electrochemical determination of methyldopa drug in the presence of diclofenac at a nanostructured electrochemical sensor

“…The solution was passed through a filter and diluted with PBS (pH 6.0) in a series of serial dilution to give a final nominal concentration of 20.0 µM and analyzed[20].Serum sample was obtained and stored frozen until the analysis. Serum sample was diluted with PBS (pH 6.0) and then appropriate volume of this diluted sample was transferred to the electrochemical cell and different amounts of MD were added and the recovery percent was obtained by DPV technique and standard addition method[51].…”

(Bio)electroanalytical Applications of Carbon Nanoparticles

“…The percolation paths are also formed in polypyrrole 47, Nafion 25–28, 48, 49, polyvinyl alcohol 50 polyethyleneimine 51 chitosan 52 and sol‐gel processed hydrophilic 53, 54, hydrophobic 42, 55 or imprinted 56 films with encapsulated CNPs. Hydrophilic carbon nanoparticles are even successfully encapsulated in hydrophobic sol‐gel processed film functionalized with octyl chains 42.…”

“…In other example hydrophobic film is formed around hydrophilic CNPs on the surface of the specific bulk substrate – carbon ceramic electrode consisting sol‐gel processed hydrophobic matrix with encapsulated graphite microparticles 55. CNPs were also encapsulated in polymeric film by electropolymerisation of pyrrole in CNPs suspension 47. Specific example is a thin belt consisting hydrophobic silicate and hydrophilic CNPs 57.…”

“…The separation between signals resulting from the oxidation of dopamine (DA) and ascorbate (AA) was demonstrated and the sensitivity of this electrode reaches micromolar level. Electrode modified with CNPs encapsulated in polypyrrole film was successfully applied for determination of methyldopa in micromolar level in the presence of interferrents as AA and uric acid (UA) and also in serum 47.…”

Electrosensing of an alpha-adrenergic agonist psychoactive methyldopa using a sodium bentonite–graphene oxide nanocomposite

“…The proposed electrochemical sensor (using DPV method) was applied for the analysis of MD in pharmaceutical products in 20 order to examine the accuracy and reliability of the proposed method. The corresponding results of tablet analysis are shown in Table 3.…”